August 26, 2008

Producers Go High Tech Against Germs

WASHINGTON - Could food producers literally squeeze the salmonella out of a jalapeno? Or zap the E. coli from lettuce without it going limp?

Headline-grabbing food poisonings from raw foods are raising interest in technology - from super-high pressure to irradiation - to get rid of some of the bugs.

Washing, even with chlorine or other chemicals, only gets rid of surface contaminants, not germs that sneak inside the fruit or vegetable. Enter high-tech options.

At a Virginia Tech laboratory this summer, food scientists subjected small grape tomatoes to what's called "high pressure processing" to see if they could squeeze salmonella to death.

It's been known for decades that massive pressure can destroy certain pathogens. The question is how to kill the bugs without smushing the food they're in.

The key is to choose a water-packed food with few air pockets. Put it in water and apply pressure evenly to all sides. Air pockets will collapse but waterlogged tissue is more resistant.

For delicate raw produce, sliced fruits and vegetables seem to be high-pressure processing's, or HPP's, main niche, says Errol Raghubeer of Avure Technologies, the Kent, Wash.-based company that makes high-pressure processing equipment trademarked "Fresher Under Pressure."

A different approach under consideration by the Food and Drug Administration is irradiation, zapping fruits and vegetables with enough electron beams or other radiation to kill germs.

Irradiated meat has been around for years; it's considered particularly useful in the ground beef that is a favorite hiding spot for E. coli. And while irradiated foods initially caused some consumer concern, government scientists make clear that the food itself harbors no radiation.

In studies of bagged salads, tailored irradiation doses killed E. coli on nine different types of lettuces without harming the texture or affecting the taste of accompanying ingredients such as tomatoes and cucumbers, says Jeffrey Barach, the director of the Grocery Manufacturers Association's food laboratory. Killing salmonella takes a little more energy, so producers would customize the beam to the need.

Mr. Barach's trade association has petitioned the FDA to allow the irradiation levels, somewhat lower than meat requires, for produce pathogen and other ready-to-eat foods, and hopes for approval by year's end.